hypermiling potential: automatic vs manual trans - Page 2 - Fuel Economy, Hypermiling, EcoModding News and Forum

euromodder · 06-11-2013, 06:33 PM

Quote:

Originally Posted by Diesel_Dave

In the past I've said that I regard the automatic transmission as an evil, destructive technology...in the same category as nuclear weapons, nerve gas, and torture devices.

Better change that opinion on the tranies ...

The most modern automatics are coasting OUT of gear when the throttle is released - examples are the VAG DSG-7 and ZF8 in their latest guises.

These are the automatics that were already beating normally driven manuals on the NEDC cycle - even before adding the coasting option.

Diesel_Dave · 06-11-2013, 10:13 PM

Quote:

Originally Posted by euromodder

Better change that opinion on the tranies ...

The most modern automatics are coasting OUT of gear when the throttle is released - examples are the VAG DSG-7 and ZF8 in their latest guises.

These are the automatics that were already beating normally driven manuals on the NEDC cycle - even before adding the coasting option.

My statement was intentionally melodramatic, and you are correct that automatics have come a long way in efficiency in recent years--particularly dual clutch technology.

That being said, a properly driven manual should never be beaten by an equivalent automatic. The biggest reason is that a good driver with a manual transmission can do one thing better than an automatic ever will--anticipate the future.

SentraSE-R · 06-12-2013, 12:53 AM

Quote:

Originally Posted by Old Tele man

135% for AT? Obviously, you haven't driven a 2011 LTZ Cruse with it's 'erratic' 6-speed automatic with its 'tall' 3.87:1 final drive ratio, have you?

No, I haven't. But one exception does not make the rule. Newer ATs are getting harder to outsmart, but the market still offers dinosaurs like the 4 speed U241E offered in the current Scion xB, 2011 Toyota Matrix, and 2010 Scion tC. The current Toyota Yaris, Toyota Corolla, Nissan Versa, Dodge Journey, Subaru Forester, Chrysler 200, Ford E-250, Ford Transit Connect, and Chevrolet Spark still have 4 speed AT options available, and I'm sure they outsell the LTZ Cruze handily.

Fat Charlie · 06-12-2013, 11:08 AM

Quote:

Originally Posted by euromodder

These are the automatics that were already beating normally driven manuals on the NEDC cycle - even before adding the coasting option.

Diesel Dave got it right. Under normal "shift it into D(umb) and go" conditions, ATs can be tweaked to outperform "shift it when you feel it's appropriate" manuals... but they're strictly reactive. If you want to buy a car that will perform best with minimal driver attention, get an auto. If you want to get better than that, the simple fact that you know your intentions will get you better numbers potential with a manual.

MetroMPG · 06-12-2013, 11:17 AM

There's no doubt the gap is closing.

But it's still fair to say that no automatic transmission is programmed to shift when&how a dedicated ecodriver would want it to. Some can be "forced" outside of their default programming to do things more efficiently (eg: http://ecomodder.com/forum/showthrea...rly-21149.html ).

Thus the manual advantage. (Highway/cruising gearing differences being the exception.)

gone-ot · 06-12-2013, 12:23 PM

Taking a 'cue' from the "Chicken or Egg?" conundrum: Which came first, man & hand or computers & hydraulics?

So, in light of my own personnal experience with GM's 6T40 hw/sw debacle in our 2011 Cruze, I will stick with the one with the most experience, if you please--the manual transmission--at least for awhile more.

And, that's *why* we won't be getting one of the new 2014 Diesel Cruzes--offered only with automatic transmission (dumb!)--even though we would love to get the diesel!